2006 Nissan Sentra - MPG issues

My car consum too much fuel so what is the problem.i check the injectors and plugs but still it’s consum more fuel

When was the last time you took your car to a mechanic for service?

Common reasons for this to happen:

  • Dirty Oxygen Sensor: An oxygen sensor measures exactly how rich or lean the exhaust gases are when they leave the combustion chamber. The data is used by the vehicle computer to adjust the amount of fuel entering the engine. If the sensor is dirty or failing it can lead to a drop in miles per gallon. It can also lead to failed emission tests and a rough idle.
  • Dirty Fuel Injectors: Fuel injectors spray fuel into the cylinders where it is mixed with air and ignited. Over time the fuel injector system can become clogged. This can lead to a drop in fuel efficiency as well as slow acceleration and the car not having enough power. If caught early, simply cleaning the injectors can solve the problem. As it progresses, the injectors may have to be replaced.
  • Bad or Dirty Spark Plugs: Spark plugs ignite the fuel in the combustion chamber. If they are dirty or working incorrectly, it can cause the engine to misfire, leading to poor engine performance. This can lead to a lack of power as well as a big decline in fuel efficiency.
  • Malfunctioning Mass Airflow Sensor: A mass airflow sensor detects the amount of air coming into the fuel injection system. It delivers that information to the vehicle’s computer, which crunches the numbers and then delivers the proper amount of fuel to the air in the vehicle. A dirty airflow sensor will degrade fuel efficiently and lead to a rough idle and even stalling as the problem progresses.
  • Misaligned Tires: Tires that are low or out of alignment can lead to a drop in fuel efficiency. Checking the tire pressure and have the alignment checked on regular basis can help prevent this problem.
  • Defective Fuel Pump: Fuel delivery issues can drastically affect fuel efficiency. The fuel pump pulls fuel from the gas tank to the fuel injectors. The fuel pump can become clogged or malfunction. A bad fuel pump can lead to a rough running engine because it is not getting enough fuel. This will lead to a decline in gas mileage. If this issue is not addressed it will lead to a rough, idle, sputtering and stalling.
  • Clogged Fuel Filter: A clogged fuel filter will also cause problems with gas mileage. The fuel filter screens out contaminants in the fuel, and over time it will become clogged. Fuel filters need to be replaced periodically.
  • Stuck Brake Caliper: A stuck caliper on a disc brake or a stuck shoe on a drum brake can lead to a serious decline in gas mileage. In addition, any brake issue can make the vehicle dangerous to drive. If the decline in efficiency is accompanied by the vehicle pulling to one side, the brake system should be inspected immediately.

A thermostat that’s stuck open will cause poor fuel mileage.

A bad coolant temp sensor for the computer will also cause poor fuel mileage.

If the computer see’s the engine isn’t reaching operating temperature, or thinks it isn’t because of a bad sensor, the computer will operate the engine in the open loop mode which means running the engine rich.


Car consume too much fuel . OK , what kind of miles per gallon is this person getting now ? What did they average before this problem ? How does it compare to the rated MPG ? There might not even be a problem to solve.

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The 1.8 liter engine Sentra is rated by the EPA at 24 mpg city/31 mpg highway, and the 2.5 liter version is rated at 20 city/26 highway.

Which engine does the OP’s car have?
How far below those mpg numbers is the OP’s gas mileage?

Equally important questions…
Is there a lot of junk in the trunk?
Do you typically drive in stop & go traffic?
How recently have you checked your tire pressure?
Is the weather very cold in the area where you live?
When the tires were replaced, did you buy low rolling-resistance tires?
Has the engine been maintained at least as well as Nissan specifies in their maintenance schedule?


Without knowing the MPG it’s currently getting, (and the methodology used to reach that figure), there’s no real specific advice to give.


Just as Beauty is in the eye of the beholder, so is the issue of “it’s consum more fuel”.

Unless the OP is carefully-calculating his gas mileage and comparing it to the established EPA benchmarks, we don’t really know whether his gas mileage is worse than can be expected for his make and model. But, that is an unknown at this point, along with the condition of his vehicle, its maintenance, its tires, and his driving habits.

I really hope that the OP returns to clarify these issues for us, so that we can give some advice that is relevant to his particular situation.

Does the OP warm up the car? The fuel mileage while doing that is 0 mpg.

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Additionally, if the OP is one of those people who pull into a parking space and continue to keep the engine running while searching for his cellphone, or a mask, or gloves, or… whatever… this is also a zero mpg situation. When I pull into a parking space, I immediately shut-off the engine while I look for whatever items I want to take with me when I exit the car.

Two days later, I guess that we’re not going to have any of our questions answered by the OP.

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If there’s an engine fuel/spark/timing problem serious enough to hurt MPG (due to inefficient combustion and thus excess emissions), wouldn’t that turn on the check engine light, or even make it flash?

I believe that you are correct, but unless the OP returns to expand on the skimpy statements in his post, we will never know about the CEL, or the maintenance of the vehicle, or the rolling resistance of his tires, or his driving patterns, or…